Belfast, Northern Ireland (CNN) -- Several hundred households in Northern Ireland are still without water, and thousands of homes face restrictions, more than a week after shortages began, Northern Ireland Water said Monday.

By Monday evening, fewer than 300 homes were without water, the state-funded water company said. That's down from about 800 on Sunday and 450 earlier on Monday.

Northern Ireland Water said in a statement Monday evening that fewer than 10,000 households will have supplies cut off overnight as repair work continues and reservoirs are refilled.

The statement added: "This represents a very significant reduction compared to the 40,000 supply restrictions last night. The 10,000 properties to be constrained tonight will have had access to a mains water supply during the previous twelve hours." The company said the restrictions were necessary to safeguard reservoir levels.

Nine schools will be unable to reopen on Tuesday because of damage resulting from burst pipes, the nation's Department of Education said in a statement. The number is lower than expected, as damage was reported at hundreds of schools over the holiday period. Education Minister Caitriona Ruane said repairs had been carried out.

Meanwhile, running water is still restricted in parts of the Republic of Ireland, with consumers being asked to conserve supplies. In the capital, Dublin, restrictions are expected to continue for at least another 12 days.

Northern Ireland Water said all repairs should be complete by the end of the week, but warned that more severe weather is in the forecast and asked customers to "protect their properties through cold weather to prevent frozen pipes and bursts."

The company said postal service workers have agreed to help identify leaks as they make deliveries, and a police helicopter fitted with the latest thermal imaging technology is being used to help check water mains in remote areas.

Many customers have been without running water for days, and some said they have not had a water supply for more than 10 days.

The shortage was blamed on the bursting of several major water pipes in a rapid thaw that followed record low temperatures in December.

Northern Ireland Water has said a number of pipes burst when the temperature rose from minus 16 to 10 degrees Celsius (3 to 50 degrees Fahrenheit) "within a matter of hours."

The company has drawn criticism from government officials, who held an emergency meeting on the situation last week. The company's interim chairman, Padraic White, said its response to the "unprecedented situation" was "unacceptable."