General Motors' Australian unit Holden is considering launching new hybrid and alternative fuel versions and even reintroducing four-cylinder models of its locally designed and produced Commodore line in an effort to reduce the environmental impact of its best-selling vehicle, a local report said.

According to the drive.com.au website, General Motors group vice president Nick Reilly, speaking at Holden's Melbourne headquarters, said a petrol-electric Commodore hybrid is likely to arrive at Australian dealerships within two years to bolstering sluggish large car sales and improve the line's export potential. It would also be a response to increasing environmental concerns.

"We will introduce hybrids in the next couple of years," Reilly (a former head of Vauxhall here in the UK) said.

"[The Commodore] could be one of the first hybrids you could see [in Australia from GM]. I would put a time frame on that of probably a couple of years."

Reilly stressed a hybrid Commodore would be part of a broader strategy to produce more efficient vehicles, drive.com.au said.

"In terms of speed the quickest things we can do are alternative fuels: LPG (popular with Australian taxi drivers), compressed natural gas (CNG) and E85 (an 85% ethanol and 15% petrol blend with which GM has plenty of US experience)," he said. "Those would be our priorities.

"We will bring in a full range of things over the next couple of years," Reilly added. "I think there … should be a range of solutions. I wouldn't be putting all our eggs in the hybrid basket."

"Hybrids are clearly an answer, but by definition they're more efficient and more expensive [to produce]. Other alternatives are LPG, E85 and potentially diesel. It depends which problem you're trying to solve."

According to drive.com.au, Reilly said hybrids are "where you get the biggest savings", suggesting it was high on the agenda for a brand that's seen its market share nearly halve in its native Australia since 2002.

Drive.com.au noted that former Holden chairman and managing director Denny Mooney had said previously a hybrid Commodore was high on the GM company's agenda. Current Holden chief Mark Reuss has also said a hybrid Commodore is a strong possibility.

Reilly also reportedly said a diesel Commodore is on the way, responding to a trend 'Down Under' towards more diesel-powered passenger cars. "We don't yet have a diesel Commodore but that will come," he said.

He also confirmed a four-cylinder Commodore was being "looked at". "It makes a lot of sense [to offer a four-cylinder Commodore] and therefore we're probably looking at it, but I can't tell you when." Drive.com.au said that engine would likely be a two-litre four-cylinder turbocharged engine slated for use in the Chevrolet Camaro, which shares its underpinnings with the Holden Commodore. Holden engineers helped develop the redesigned Camaro locally and the revived version of one of America's most famous nameplates goes on sale in the US next year.

Holden began in 1948 as a local manufacturer of six-cylinder models, adding V8s late in the 1960s. It initially sourced four-cylinder cars from Vauxhall in England for local CKD assembly in the '50s and '60s and later adapted the British Viva to create its first locally-made small, four-cylinder car, the Torana, in 1967.

The third generation Torana launched in 1974 was originally planned with four- (imported from Opel), six- and eight-cylinder engines. However, the two 1970s oil crises turned buyers more strongly towards fours and, in 1980, the company created its own 1.9-litre I4 engine for the Torana and its Sunbird successors, and the then-new Commodore, by simply lopping two cylinders off its 2.2-litre I6.

That engine, which sold best in neighbouring export markets like New Zealand (where tax rules favoured sub-two litre engines), was available in Australia until 1984 and exported until 1986 when Holden switched to fully-imported Nissan I6 engines for the Commodore to meet strict new Australian emissions rules.

The 1988 VN Commodore switched engine source again - to local assembly of 3.8-litre Buick V6 engines imported from the US plus an Australian V8, later replaced by a US unit. Four-cylinder VNs were made for New Zealand, and some other export markets, with German two-litre Opel engines but these did not remain long in production.

According to drive.com.au, Reilly said the company would not, however, be walking away from the performance (ie V8) market that now makes up a significant share of its Commodore sales.

"We're going to stay very strong in those things [performance cars], because you don't wipe out a love and a heritage for those type of vehicles … and it's what we know a lot of people in Australia enjoy," Reilly said. "We're not reducing out efforts in that area."