CFMEU vice-president Wayne McAndrew said the march along Remembrance Driveway was about getting a message out to the community.

"Tahmoor coalminers and their families are saddened at the fact that a big rich mining company is not prepared to guarantee job security and safety standards," Mr McAndrew said.

About 300 joined the march and meeting at the Tahmoor Inn, with workers wearing shirts saying "Xstrata: condition killers".

Mr McAndrew described the attendance at the march as "fantastic" and said the union was prepared to "step the action up as we move forward".

"The negotiations are ongoing."

Mr McAndrew said people in the Tahmoor community could show their support for the coalminers and their families by signing the workers' petition or by putting an "Xstrata - Community Hazard" sign in their front yard.

The union argues flexible working conditions in the agreement erode their entitlements. The strike follows several other forms of industrial action, including reduced work output over recent months.

Xstrata has presented two new agreements to the union, both of which have been rejected.

Xstrata also cut 158 jobs from the mine in September.

Xstrata Coal communications manager James Rickards said the agreements offered were in the best interests of employees and the "future viability of the Tahmoor operation".

"Tahmoor management have offered wage increases of up to 16 per cent for employment conditions that provide no greater flexibilities than those currently available under the new 2010 award that was negotiated by the CFMEU under the current federal Labor government," he said.

"These ongoing strikes demonstrate this industrial campaign is not about Tahmoor and unfortunately our Tahmoor employees are being used as a broader CFMEU campaign against Xstrata Coal."