Four major mobile phone carriers in Japan have come out with relief measures for subscribers affected by Monday's devastating earthquake in central Japan.

NTT Docomo says it is offering reduction or exemption of basic fees for fixed-line communication services, as well as repair services at discounted or no costs.

The carrier has also lifted restrictions on transmission speeds that would kick in when mobile phone users exceed their data usage contract.

KDDI is offering reduction or exemption of basic fees for fixed-line communications and deferral of payment deadlines for mobile phone services. It has also reduced or exempted handling fees that users need to pay when they want to replace their smartphones after losing them or finding them damaged.

KDDI has also lifted restrictions on transmission speeds when mobile phone users exceed their data traffic contract.

SoftBank is similarly offering reduction or exemption of basic fees for fixed-line communications and deferral of payment deadlines for mobile phone services.

It is also offering mobile phone repairs for reduced or at no cost, as well as free exchange of equipment for fixed-line services.

Rakuten Mobile says it will charge no fees for reissuing SIM cards and will postpone the payment date for subscription fees.