BANGKOK (Bloomberg) - The United Nations said on Friday (April 22) Thailand's military government must suspend laws giving soldiers power in policy making and law enforcement, as well as open space for debate over a proposed constitution.

UN High Commissioner for Human Rights Zeid Ra'ad Al Hussein said he was concerned that there would be an increased crackdown on criticism ahead of the Aug 7 referendum on the junta-drafted charter.

The junta, which seized power in a May 2014 coup, has warned that anyone campaigning against the draft could face 10 years in prison.

"An open and dynamic public debate on the draft constitution would foster national unity, strengthen the legitimacy and acceptance of the constitution and provide a sense of collective ownership," Zeid said in a statement.

"I urge the government to actively encourage, rather than discourage, dialogue and engagement on the draft."

The draft was written by a committee hand-picked by the junta and has been denounced by both of Thailand's major political parties, who warn it is undemocratic and would prolong the military's presence in politics.

The UN said the draft "institutionalises the role of the military in policy making and law enforcement."

"Extending the military's powers is not the answer to rebuilding Thailand's political landscape," Zeid said. "On the contrary, Thailand has competent civilian institutions and should be looking to strengthen the rule of law and good governance, not undermine it."

Election Threatened

Junta leader Prayut Chan-o-cha warned on Thursday that protests and dissent could endanger the referendum and a future election. The junta has repeatedly pushed back the date for possible elections, with the latest timeline calling for polls in late 2017.

Prayuth also brushed off international concern about the detention of critics, saying he would send a letter to diplomats explaining Thailand's current situation. Thailand's foreign ministry sent media a document Friday, restating the government's talking points that it was working to reform the country and lay the foundation for a return to democracy.

The ministry said "public order and social harmony" were needed if the government were to complete its work and that's why it had enacted various laws.

"These laws do not impinge on general freedom of expression -- which we believe to be a fundamental element of a democratic society -- as long as such expression does not undermine public order and social harmony," it said.

"In fact, the government has been receptive to all views regarding the current process of reconciliation and reform."