New Zealand's A1 Grand Prix drivers are promising to support each other during Round 3 of the World Cup of Motorsport in Portugal this weekend, regardless of who is behind the wheel.

Matt Halliday drove the Black Beauty to a 3rd and 4th during last month's inaugural round at Brand's Hatch while Jonny Reid was similarly impressive in recording two 4th placings in Round 2 a fortnight ago in Germany.

Those results have propelled A1 Team.NZL to second-equal with France on the championship table, just one point behind Brazil, and Chief Executive Bob McMurray says the team is in a healthy, but awkward, position having two drivers "who are equally as good and fast."

"The decision as to who drives at Estoril this weekend wouldn't be easy," McMurray said. "Down the track there may be instances where one driver shows particular aptitude on a certain circuit, but at this stage there's nothing really separating Matt and Jonny.

"We're lucky this round that we have an extra practice session to give our second car its first shake-down. That will give us more time to evaluate the drivers' performance on this particular track and make a definitive choice."

Jonny Reid, who celebrated his 22nd birthday yesterday, did not want Halliday to have a very happy return from racing at Bathurst.

"Personally, it was quite hard for me to dip out on driving at Brand's Hatch and it's a difficult situation to watch someone else taking the opportunity," Reid said.

"But it's the way A1 is. Because you're representing your country you have to look at the greater good. I'm more relaxed now because I simply have to be. There's nothing I can really do apart from prepare as well as I can and take the opportunity if it arises."

Halliday says he was frustrated to "get out of the rhythm of A1" to honour his commitment to drive at Bathurst, but he is focused on slipping back into single-seater mode.

"We're both competitive people, as you have to be in motor racing at this level," Halliday said. "I want to be in the seat as much as possible, but I'll be putting in one hundred per cent even if they do decide to go with Jonny.

"This is a team game and you have to support the other driver. There's no benefit to going all Tonya Harding on a team mate."

Both drivers suspect the wheelman will be alternated, practically from round to round, in an approach that they believe has its pros and cons.

"It does keep you on your toes," Halliday said. "There can't be any let up or you'll find yourself on the sidelines."

"Having the two of us at a comparable level does ease a bit of pressure and will obviously ensure one guy doesn't get burnt out, but it does make it more difficult to prepare properly," Reid said.

"You just have to keep fit, stay focused and mentally prepare as if you will be driving anyway."