Changes to Tasmania's Aboriginal Heritage Act have been criticised for not going far enough and should include measures such as land acquisition, an Aboriginal group says.

The Tasmanian Aboriginal Centre (TAC) said most of the proposed changes were ones the community had been urging Governments to make for some time.

The Government is looking at tougher penalties for vandalism, changing the name of the Act and setting a statutory timeline for another review of the laws.

It will also remove the defence of ignorance when relics are damaged.

It comes as police investigate the vandalism of rock paintings in the Central Highlands, believed to be 8,000 years old.

TAC chief executive Heather Sculthorpe told 936 ABC Hobart the community did not criticise the Government for doing "a quick patch up" of the act but more could be done.

The TAC believes the Government should consider land acquisitions as a means of protecting important heritage like rock art.

"They are ruling out acquiring pieces of land, buying up buffer zones to [ensure] protection," she said.

Ms Sculthorpe welcomed tougher penalties.

"Yes they have got to increase the penalties and he [Minister Matthew Groom] talks about removing the defence of ignorance, but there is nothing anywhere to indicate that he is actually going to do that," she said.

"In fact, the reverse is true.

"By saying you have to be reckless, negligent or know what you are doing — so having it as an offence of strict liability where if you destroy Aboriginal heritage you are liable — the onus is on you to know the law, as it is in many other parts of the law, like workplace safety.

"There is really no excuse anymore for people not to know it, so that is one of the things where he has got to change his thinking."

1876 'cut off' date to be removed

Under the changes, the 1876 "cut off" date for defining Aboriginal heritage will also be removed.

The date marks the death of prominent Aboriginal woman Truganini, inferring that anything made after that date had no heritage value.

The Aboriginal community has long lobbied for the date to be removed.

"There is a limit to how much praise you can heap on someone who is finally recognising that, so yes it's good but it is very late in coming," Ms Sculthorpe said.

A public input period is open until the end of July and the Government wants to introduce legislative changes to Parliament by the end of the year.

Ms Sculthorpe said the community was still waiting for "a proper Aboriginal Heritage Act".

"No-one has been able to do it yet," she said.

"We have told them the principles that should guide them in the rewrite of the Act and there is nothing really to say that they are going to adopt what we are saying.

"Principally, it is about Aboriginal ownership of Aboriginal heritage."