Act leader Rodney Hide says his party is thriving in partnership with National - a stark contrast to a warning from one of his MPs that it is losing its way and risks becoming irrelevant.

Hide paraded policy successes in his speech to Act's annual conference yesterday, saying it was delivering stable government while breaking through with tough law and order legislation, clearing out red tape and setting a goal to catch up with Australia's economy by 2025.

"Against all predictions, against all odds, we have thrived," he said.

"Act is demonstrably making a policy difference. But the most important difference we have made is lifting the sights of the Government, and the country."

Hide repeatedly emphasised the importance of working with National through the agreement it signed after the last election, and keeping its promise to ensure stable government.

Last night Sir Roger Douglas, a founder of the party and a list MP since the last election, told the conference Act was in "real danger" because the success it had achieved in government was not reflected in the opinion polls or any other measure of support for the party.

"We need to engage in an internal debate to figure out what we are doing wrong, and how we can do better," he said.

Sir Roger said Act risked being stranded in the middle ground of New Zealand politics because that was where National was heading.

The sharp difference between the speeches demonstrated the long-standing disagreement between Hide and Sir Roger about the party's direction.

Both denied there was a rift.

Sir Roger said his speech was not an attack on Hide, and he believed every party had to take time to look at itself and its direction.