They can't do it. They even didn't have any power to ban users. How could they stop technology? now days is modern and we need a good e-money like bitcoin. Even they block up the IP of users, we could do VPN or another IP changer to fake it out and access bitcoin site normally.
May. They can not ban people from working and collecting Bitcoins because Bitcoin is always secure and safe for users. But the government has the right to prohibit the use of Bitcoin in trading activities. At the same time tightening management of banks involved in the conversion, exchange Bitcoin to cash. They are responsible for their country. And they have the power to issue bans. Hopefully in the future, the government will have a more positive solution.