For a century Girl Guides have promised to do their duty to God and serve the Queen.

But Girl Guides Australia is about to embrace a new promise, and they have removed any reference to the Queen and God.

The move comes in a jubilee year, but Girl Guides Australia director Belinda Allen says the timing is right.

"The Queen was contentious with a number of our members, not all our members by any means," she told Lateline.

"It was very much felt that she wasn't the word required, but people could very much serve her by serving Australia."

The move follows 18 months of consultation with thousands of members of Australia's largest volunteer girls group, most of them girls between the ages of 10 and 14.

The old Guide Promise I promise that I will do my best:

To do my duty to God, to serve the Queen and my country;

To help other people; and

To keep the Guide Law. The new Guide Promise I promise that I will do my best: To be true to myself and develop my beliefs To serve my community and Australia And live by the Guide Law.

Ms Allen says the decision is controversial among older members in the group's 800 districts.

"It's been a huge, huge decision and it hasn't been taken lightly at all," she said.

"We very, very much respect for many of our members that's a promise that's dear to their heart and that's a promise they made as a young women and they have lived by all their life."

The removal of Her Majesty will be optional, and as a residual mark of respect the name of the guide's highest honour - the Queen's Guide - will not change.

Guide leader and Queen's Guide Gillian Garsia agrees it is time to modernise, but admits it is a bit of wrench.

"We've always loved the Queen in my home and watch all the celebrations," she said.

"[We have] recently been glued to all the jubilee things. I see her as our head of state."

In the new promise, duty to God is also gone.

"Our members didn't feel 'duty to God' reflected all faiths and belief systems across the world," Ms Allen said.

That sentiment was echoed by Portia Lander-McLeod, a Girl Guide aged 12.

"All girls can be guides it doesn't matter who you are or what religion or anything," she said.

For guide leader Susanna Matters it is a welcome change. She is Jewish and it never really made much sense.

"The new promise is actually a better fit for Jewish people in that sense but I think the new promise is a better fit for everyone," she said.

In its heyday the Girl Guide movement in Australia boasted 80,000 members.

Now it is closer to 30,000 and Ms Allen acknowledges the changes are designed to boost its membership from any faith or culture.

"We are very much hopeful with the new wording to the promise that we'll be seen as more inclusive and modern and relevant organisation and many more people will like to join us," she said.

In the new guide law, loyal has been replaced with respect, and helpful replaced with considerate.

Obedience has been abandoned and instead girls are encouraged to make choices for a better world.

"With equality and women obedient is not an appropriate word to have in a promise and our members very much told us that," Ms Allen said.